The present invention relates to a control method for a multiprocessor system.
As for conventional data transmission and reception control methods for multiprocessor systems, a command/response scheme is used in a high level data link control (HDLC) procedure or the like as described in "Information Processing", Information Processing Society of Japan, Vol. 23, No. 12, 1982, pp. 1154 to 1160. This scheme is one-to-one communication wherein a processor for transmitting data specifies a processor which should receive the data, and the processor which has received the data transmits a response indicating success in the reception on the data to the processor which has transmitted the data. The processor on the transmission side detects success in the data transmission upon receiving the response, whereas the processor on the transmission side detects failure in the data transmission on the basis of the fact that the response is not returned. This scheme is based on the assumption that the processor on the transmission side knows the address of the processor on the reception side.
Further, there is also a broadcast system in which data is transmitted without specifying a specific receiving processor, and all processors within the system receive the data. In this system, the response confirming the reception of data from the receiving processor is not transmitted. Even if a fault occurs in a processor within the system or a processor is newly added, therefore, the processor on the transmission side can transmit data without being conscious of such a fact.
In the one-to-one communication which is the above described related art, data omission at the data transmission level is not caused because a response is returned for every transmission. Since the one-to-one communication is based on the assumption that the processor on the transmission side knows the addresses of all processor on the receiving side, however, it is necessary to inform all processors of a change in system configuration caused by expansion, a fault or the like, resulting in a problem in expandability. In broadcast communication, such a need is obviated and expandability is high. Since a response is not returned, however, there is possibility that data loss is caused when an increased load causes overflow of a receiving buffer and broadcasted data cannot be received, for example.